This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This study will use three-dimensional probabilistic mapping techniques to delineate extrahippocampal anatomical abnormalities in patients with mesial temporal lobe epilepsy (MTLE) with hippocampal sclerosis (HS), and correlate them with surgical outcome and post-operative cognitive profile. The study is being done in collaboration with Paul Thompson, PhD. who has developed a new computational technique that takes into account normal variations in gyral pattern across subjects. Thus, in this probabilistic morphometric technique, abnormal gray matter distribution can be distinguished from and related to the gyral anatomy of the individual.In the first phase of this study, deviations in gray and white matter distribution of patients with MTLE and HS with good surgicaloutcome will be averaged together retrospectively to construct a disease specific atlas. In phase two, comparisons will be made prospectively between individual anatomical deviations in gray and white matter distribution and the disease specific atlas in order to delineate individual extrahippocampal structural abnormalities. Correlations will be made between individual structural abnormalities and post-surgical cognitive outcome and seizure freedom. We will define anatomical regions in which regionally specificdeficits correlate best with clinical and cognitive parameters.